Vidiot (brown@xxxxxxxxxxxxxxxxxx): > > One annoyance with DV for NTSC is that it's 4:1:1 and converting > > from 4:1:1 to the 4:2:0 you need for MPEG-1/2 is a pain to do well. > > Still, that sort of annoyance is best left to those seeking > > ultra-correctness. > > Not had a problem so far. Unfortunately at this point it has all been > done under Windbloze. But, a friend has been playing with Linux tools > and as far as I know, hasn't had a problem either. At some point, someone has to convert from 4:1:1 to 4:2:0. Linux tools currently seem to simply duplicate chroma samples horizontally and drop vertically, resulting in poorer colour than could be achieved with a better filter. Test images to show problems would likely have jagged blue or red edges. > >> BTW, before going to VCD and/or DVD, the NTSC setup level needs to > >> be removed. So whatever tool you use, make sure that it can remove > >> NTSC setup, as the MPEG-1/2 standard does not use it and leaving it > >> in will cause problems. > > > > What are you talking about here? The Y'CbCr specs for MPEG-1/2 are > > the same as for DV. Please clarify. > > Please read what I wrote. I said that the "NTSC setup" needs to be > removed. Most consumer, and even pro-sumer, devices will not remove > NTSC setup when fed an analog signal for conversion to DV. The setup > is left intact in the DV data. My DVCAM decks are like that. No > switch to tell it to remove, or add, setup. It records what you feed > it. Ok I see what you mean. We discussed this before about how to properly cut it off. So, let's say I'm trying to get rid of the setup. Should I record at like 768x480 and then estimate where the setup ends, and then resample the active area with 720 samples ? I can't see how to do this though without messing up the aspect ratio of the content. -Billy
